what makes a cavity good - the budker group.pptx

What makes a cavity good?Dan BrooksApril 29, 2008Physics 250Overview?Introduction to Cavity QED?Nanomechanical Oscillators?Our Experiments3Cavity QEDNanomechanical OscillatorsOur Experiments?Fabry Perot Cavity–Free Spectral Range–Linewidth (2κ)–Finesse ( )Some Cavity Basicshttp://en./wiki/Fabry-PerotCavity QEDNanomechanical OscillatorsOur ExperimentsOptical Cavities?Planar Cavity?Confocal Cavity?Near-Planar CavityCavity QEDNanomechanical OscillatorsOur ExperimentsOther Optical Cavities?Half-Planar Cavity?Toroidal ResonatorT. Aoki, et. al., Nature 443, 671-674 TP Purdy, DM Stamper-Kurn - Applied Physics B 90, 401-405 (2008)Cavity QEDNanomechanical OscillatorsOur Experimentseg?Cavity couples to a two-level system (. an atom)?Detunings that matter?Δca= ω cavity - ω atom ?Δcl= ω cavity - ω laser?ΔN = n-atom cavity shiftCavity QEDNanomechanical OscillatorsOur Experiments?γ= spontaneous emission?κ= cavity decay rate? g = coupling strength parameter–where d is dipole matrix element of atom–Vc is mode volume of cavityγgκ8Cavity QEDNanomechanical OscillatorsOur ExperimentsDressed Atom Picture?σ are Pauli spin matrices describing atom’s state. σ+=|e><g| and σ-=|g><e| ?The rotating wave approximation has been used to eliminate counter-rotating terms?The Hamiltonian has eigenvalues:?For many atoms:Cavity QEDNanomechanical OscillatorsOur ExperimentsDressed Atom PictureCavity Detuning (length)Energy00AtomicResonancegN?2NgCavity QEDNanomechanical OscillatorsOur ExperimentsDressed Atom PictureCavity Detuning (length)Energy00AtomicResonancegN?2Ngfrequencybare cavityresonance?N=Ng2/?cshifted cavity resonancedetunedprobe ΔclKaterMurch AMO Seminar 2007